Batery Lab (Concentration of Salt) By:Evan

Problem: How do we design the best possible battery cell?

Hypothesis: We believe that if we changed the concentration of the salt in the water we would have an increase of curent. This is because we know that batteries involve acids and we assume that the more power or concentration of these acids in the battery the more power it will have.

Formula: y = m x + b is what we are expecting because or dependent variable is consistent except for the Saturate and 0g.

Procedure:
  1. Fill 11 large beakers with 100 ml of tapwater using a syringe and a 100ml small beaker
  2. Label the 11 beakers a,b,c,d...ect
  3. Measure out .5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5,5.0 g of salt and add into test tubes (label quantities) (this can be done using scale and scoopilla)
  4. Add each quantity to each beaker .5g(a), 1.0g (b)...ect (the last beaker should only have water in it)
  5. Mix all the salt so that it is fully disolved into the beaker
  6. Add 1 copper rod and 1 bronze rod to the beaker you want to test (rods can't be touching)
  7. Attach 1 aligator clip to each of the rods
  8. Attach the multimeter to the other end of the aligator clip.
  9. Record the voltage and the current
  10. Take the metal rods and put them into the next beacker
  11. Record the voltage and the current
  12. Measure the voltage and current for each beaker
  13. Record observations and results
lab_demo_1
Materials
  • Salt or 27.5g of salt.
  • 10 large beakers
  • tap water or 1.1 L of water
  • 2 crocodile clips
  • 1 Multimeter
  • 1 scoopila
  • 1 scale
  • Syringe
  • Stiring rod
  • 1 bronze rod
  • 1 copper rod

Conditions and Constant Variables
  • Temperature
  • Amount of water
  • Size of beaker
  • Type of salt
  • Type of metals
  • Same multimeter
  • Same testing area.

Observations
Beaker
Voltage
Current
a (.5 g)
.55
.91
b (1.0g)
.55
1.02
c (1.5g)
.55
1.21
d (2.0g)
.53
1.24
e (2.5g)
.54
1.21
f (3.0g)
.54
1.19
g (3.5g)
.55
1.25
h (4.0g)
.55
1.95
i (4.5g)
.59
1.14
j (5.0g)
.53
1.71
k (0g) (water)
.53
.59
l Saturated
.56
1.9




science.JPG


science_22.JPG


Our hypothesis didn't work as well as we planned during the experiment. What we found was that when the concentration of salt increases, the voltage of each of our mini battery cells does not increase by a significant amount. Also, looking at our results, we got a varying voltage throughout the test. The current however, did change, and though it went up, it did not change by that much. To be safe, we added a lot of salt in one of our solutions and we tested again. We found that the Voltage did not change very much but the current did. We think this is because of some of the inconsistent variables. These would be the space between the two pieces of metal and that we shook the testing table a lot disturbing the solutions. We noticed that the Voltage and the Current was quite low throughout the experiment and that changing the concentration of salt does not seem to make a significant difference in the battery cell. However, if we perhaps changed the type of salt or the type of solvent we would have different results but our results show us that the amount of salt will not make a huge difference in developing your battery. So we came up with three possible conclusions. First, the type of salt we used is not acidic enough to show the difference in current when increasing concentration of salt. Second, we think we should have added more salt in each battery to make observing differences easier. Third, concentration of salt in water might not be one of the factors that can change the current of battery. If we could test something for next time it would be the use of different salts or acids to create a more powerful battery cell.

By:Evan


Evaluation and Summary of Experiment-Concentration of salt: Kevin Lo

For our hypothesis, we assumed that current would change according to the concentration of salt in battery. To explore the connection between salt concentration and current, we made the varible the concentration of salt. During the experiment, we tried to keep every other variables as constant as possible and have our observations as precise as possible. However, the results that we observed was not as expected. We expected that the slope of voltage should increase. But the results showed that the voltage just changed randomly and did not have a pattern of change. For the current, it had no big difference in the first decimal place, and huge differences in the second decimal place. However, pattern of current was not observed. Our conclusion of this experiment was that the concentration of salt does not really consider as a factor of changing the current or voltage.
Beaker
Voltage
Current
A (.5g)
0.55
0.91
B (1.0g)
0.55
1.02
C (1.5g)
0.55
1.21
D (2.0g)
0.53
1.24
E (2.5g)
0.54
1.21
F (3.0g)
0.54
1.19
G (3.5g)
0.55
1.25
H (4.0g)
0.55
1.95
I (4.5g)
0.59
1.14
J (5.0g)
0.53
1.71
K (0g-water)
0.53
0.59
L (satured)
0.56
1.9